Study On The Influencing Factors Of Male Semen Quality And Its Relationship With Trace Elements Zinc And Selenium In Semen

BackgroundAffected by factors such as stress in life,unsafe diet,and environmental pollution,the incidence of infertility among married couples in the world is increasing,accounting for 12%-20%of the fertility population.Sperm counts of normal fertile men has fallen by nearly 50%in the past 40 years.Among the many factors that cause male infertility,semen quality abnormalities accounted for 32%and 57%,respectively,and has becoming the main cause of male infertility.There are many factors that affect the quality of semen in men.General demographic characteristics,lifestyle habits,dietary habits,and environmental exposure can all lead to abnormal semen quality.Trace elements in the human body are also closely related to semen quality.Although the content of trace elements in the body is extremely small,the trace elements have very powerful biologic effects.Excess or inadequate intake of trace elements could induce biological abnormalities or cause diseases.Many trace elements affect the male reproductive system,among them zinc and selenium are closely related to male infertility.This study aims to demonstrate the influencing factors of male semen quality and its relationship with trace elements zinc and selenium in semen.The reseatch will provide reference for health care and clinical treatment.Materials and MethodsThis study was designed as a cross-sectional epidemiological survey,combined with laboratory experiments and clinical testing.The male adults who came to some three-level hosipital in Shenzhen seeking fertility treatment and consultation are our study population.Additionaly,the men who are willing to response to our questionnaire survey and provide semen sample were recruited in this study.Exclusion criteria include having a reproductive disease,birth defects,patients who have recently been administered drugs that affect semen quality(such as spermatogenic capsules)in the recent half year,patients with blood disorders,patients with endocrine system diseases and genetic histories of reproductive system diseases.The trained investigators used a unified questionnaire to record demographic data and clinical data for all subjects,including general demographics,lifestyle habits,dietary habits,past medical history,and medication history as well as collection their semen.According to inclusion and exclusion criteria and screening questionnaire,1015 cases were recruited in our study.All subjects should be abstinent for 2-7 days.Semen collection was conducted strictly on the basis of the fifth edition of the WHO Laboratory Manual for Laboratory Testing of Human Semen and Sperm-Cervial Mucus Interaction.Moreover,a semi-automatic computer-assisted sperm analyzer(CASA)was used for semen quality analysis.Inductively coupled plasma mass spectrometry(ICP-MS)was used to evaluate the content of zinc and selenium in semen.Data was recorded and checked by using Epi-Data software,and the statistical analysis by SPSS 19.0.Quantitative data are described using the mean and standard deviation of the normal distribution.Group comparisons are compared using one-way analysis of variance.Median and interquartile ranges was used to describe the characteristic of abnormal distribution,and the difference between these group was analyzed by Kruskal-Wallis H test.Categorical variables were analyzed using chi-square test or Fisher’s exact probability method.Correlation analysis of quantitative data was performed using Spearman rank correlation analysis;correction confounding factors were analyzed by partial correlation analysis;The regression model was used to analyze the relationship between semen zinc and selenium content and general demographic characteristics,living habits,dietary habits,and sperm quality.All statistical analysis with P<0.05 for the difference is statistically significant.ResultsA total of 1,015 adult males were included in the study.The general demographic analysis showed that the average age of subjects was 31.8 ± 6.1,which the proportion of people under 40 was the highest(87.9%).The proportion of Han Chinese account for 96.5%,and Zhuang Chinese account for 2.4%.The academic level of the research subjects is mainly universities and high schools,accounting for 78.1%.The occupations of the research subjects are main business services and medical education,which are 35.7%and 31.5%,respectively.The proportion of farmers is low,just accounting for 0.2%.Approximately,one-third of the target families’ annual income is 72,000 to 12,000 yuan.About 40%of the subjects had been pregnant,and 23.1%had ever had children.32.3%of the study subjects had smoking history,14.7%had drinking history,63.3%used to wear leggings,48.4%used to do physical exercises,and 91.3%of them sit within 9 hours a day.62.5%were engaged in moderate work.The dietary habit of study subjects were mostly combined with meat and vegetables,which accounted for 80.7%.Cereals,meat,fish,shrimps,eggs,dairy products,soy products,fried foods,desserts,fruits,and vegetables had a preference ratio of 22.8.%,34.5%,21.8%,17.9%,10.8%,11.7%,9.5%,8.1%,23.1%,33.1%,respectively.The median concentration of semen zinc was 152.214 mg/L;P25-P75 was 106.18-214.56 mg/L.The selenium concentration in the semen was 55.132 μg/L;P25-P75 was 43.019-71.272 μg/L.The results of Spearman level correlation indicated that there is a positive correlation between semen zinc and selenium content(rs=0.657,P<0.001).The results of univariate analysis showed that selenium concentration was higher in the semen of 40-year-old semen;the concentration of selenium in semen of the drinker was higher than that of non-drinkers;the concentration of selenium in semen of subjects who often perform physical excersice was higer than the sedentary people.There was no statistically significant difference in demographic characteristics,lifestyle habits,and dietary habits of subjects with different concentration of Zinc in semen.As the duration of abstinence increased,the volume,concentration,and sperm count of semen increased,while the PH value and forward movement rate decreased.After adjust the abstinence days by the mixed linear model,we found that the semen volume,total sperm count,forward movement rate,and total vitality in three low-age groups(20 years old,30 years old,and 40 years old)were higer than the the 50-59-year-old group.Moreover,our study also found out that general demography characteristics have impact on the quality of semen.The education level has an effect on the semen’s PH value.The family’s annual income could influence the forward movement rate and total vitality of the semen.Interstingly,the total number of spermatozoa of the farmers is highest,followed by the workers.The volume of semen volume and the total number of spermatozoa in subjects who often perform physical excersice than those inactive.The subjects with a a daily duration of 6 to 9 hours sitting has the higest concentration of spermatozo.The different eating habit has no effect on the quality of semen in our study subjects.After adjusting abstinence days,the PH value,the volumn of semen and the forward movement rate in the group with low concentration(<20%)of semen zinc was higer than the group with hige concentration(80%～).The volumn of semen in the group with low semen selenium concentration(<20%)was larger than the group with hige concentration(80%～),and the semen volume increases along with semen selenium concentration.The sperm density and total spermatozoa in the group with high semen selenium concentration(80%～)was higer than the group with low semen selenium concentration(<20%),moreover it was decrease along with the increase concentration of semen selenium.After adjustment for abstinence days,the results of the correlation analysis showed that the semen zinc had a weak negative correlation with the semen’s semen volume.The correlation coefficients were-0.127.The concentration of semen zinc was positively correlated with sperm concentration(rs=0.264);the concentration of selenium in semen was a positive correlation between the sperm concentration(rs=0.411)and the total motible spermatozoa(rs=0.260).The results of Logistic regression analysis indicated that highly educated subjects such as post-graduate student,undergraduate and college had lower relative risk in oligozoospermia,with OR(95%CI)values of 0.177(0.031-1.007),0.090(0.019-0.420),and 0.185(0.039-0.865),respectively.Compared with the group with high concentration of semen zinc(>80%),the group with lower concentration had the higher relative risk in oligozoospermia,and the OR(95%CI)values were 16.673(5.883-50.004)、10.002(4.002-25.002)、5.554(2.322-14.283)、2.321(1.081-5.264),respectively.However,compared with the group with high concentration of semen selenium(>80%),the group with lower concentration had higer relative risk in oligozoospermia,and the OR(95%CI)values were 86.533(23.012-325.399),34.672(9.968-120.597),7.724(2.463-24.224),7.472(2.111-26.449),respectively.The results of Logistic regression analysis showed that subjects under 40 years old had the lower risk in asthenospermia compared with the 50-59 age group,the OR(95%CI)value of the 20～30 age group and 30～40 age group was 0.058(0.006-0.645),0.062(0.006-0.684),respectively.The smoking subjects had the high risk in asthenospermia,and the risk of asthenospermia was higher in smokers,OR(95%CI)was 2.096(1.345-3.353);The risk of the disease was lower,with an OR(95%CI)value of 0.316(0.124-0.806).Compared with 80%semen zinc,the risk of the occurrence of asthenozoospermia was higher in the<20%group,OR(95%)value is 2.218(1.508-4.378).The rusults of Logistic regression analysis of azoospermia revealed that the risk of absence of spermatozoa was lower in those who exercised regularly,with an OR(95%CI)value of 0.389(0.155-0.944);compared with 80%of semen zinc,<20%of the group,The incidence of azoospermia was higher in the 20%-group,40%-group,and 60%-group subjects.The OR(95%CI)values were 25.000(5.000-100.000),20.000(4.172-95.024),and 7.694(2.082-33.333),4.002(1.156-14.278);semen selenium 80%～compared,<20%group,20%～group,40%～group subjects have a higher risk of azoospermia,OR(95%Cl The values are 24.814(3.975-154.895),18.411(3.616-93.753),4.918(1.016-23.807).The risk of abnormal semen liquefaction in subjects with different abstinence days and different semen zinc concentrations was different.Compared with 80%semen zinc,the risk of abnormal semen liquefaction was lower in the<20%low concentration group.The OR(95%CI)value was 2.030(1.271-3.244).Conclusions1.The contents of semen zinc(152.21mg/L)and selenium(55.13μg/L)in men were similar to those in most studies,and there was a positive correlation between semen zinc and selenium content.2.The quality of semen in men is affected by age,education,regular exercise,and semen zinc and selenium content.3.Low education,semen zinc,selenium concentration is a risk factor for oligozoospermia;Infrequent athletes,semen zinc,and low selenium content are risk factors for azoospermia;Old age,low semen zinc concentration,infrequent exercise,and smoking are risk factors for asthenozoospermia;Low semen zinc concentration is a risk factor for abnormal semen liquefaction.4.Quitting smoking,exercise,and appropriate supplements of trace elements zinc,selenium help improve semen quality.